Method of converting oil



. 7, 1943. D. B. BELL METHOD OF CONVERTING OIL Filed Oct. 28, 1940 wwUmm@ www ohm

Wm, hm,

mw.. m

Lmbmmx. KONE@ QN w m INVENTOR David .5.23822 mflg my A RNEY.

Patented Dec. 7, 1943 METHOD OF CONVERTING OIL David B. Bell, LongBeach', Calif., assignor to Kenyon F. Lee, Los Angeles, Calif., astrustee Application October 28, 1940, Serial No. 353,148

6 Claims.

This invention relates to a method for conversion of hydrocarbon oils,particularly petroleum residual oils and lighter oils. This applicationis a continuation in part of application Serial No. 310,908, ledDecember 26. 1939.

The invention of this application is directed to a process of conversionof petroleum oils, of high molecular weight, as for instance, theconversion of crude oils and residual oils into gas oil and gasoline,and the conversion of gas oil and kerosenes into gasoline and fractionslighter and heavier than gasoline.

Petroleum oils and particularly heavy oils such as residual fuel oils,crude oils, heavy gas oils and heavy oils produced by cracking may beconverted by the process of this invention into lighter bodies with highyields of gasoline, light gas oils by reaction of the oil with air orother oxygen-containing gas.

In the process of my invention air has two functions. When employingheavy oils at a temperature insufficient to completely vaporize theoils, the air has the property of disintegrating the oil entering thereaction into small particles, and it has the property ofdehydrogenating the oil, whether liquid or vapor, and in so doingapparently is accompanied by cission, cyclization and aromatization.

The air and oil must be mixed in a mixing device to permit thedisintegration of the unvaporized oil into very fine particles if it isliquid, or to cause an intimate commingling of the oil if a vaporizedfeed is employed. This mixture is usefully carried out at a relativelylow temperature to inhibit reaction in the mixer, and its flowcontrolled to the proper degree, as hereinafter explained. Preferablythe mixing temperature should be below the thermal cracking temperatureof the oil. It preferably should be at a temperature at which thereaction rate between the oil and air is low so that substantially noreaction occurs in the mixing zone. If a relatively high'temperature isattained in the mixing zone the reaction proceeds rapidly in the zonewith the formation of coke, excessive gas and excessive -i combustion.The control of temperature in the mixer may be accomplished by limitingthe temperature of the oil entering the mixer, also by employing air ata relatively low tempertaure and also by employing a mixer which iscooled, as for instance, by exposure to the air, where any temperaturerise is minimized by loss in radiation and convection.

The mixture, after it is formed in the mixing tube, is expanded into anenlarged reactor-expander where there is a material drop in pressure.The nature and the elects of the expansion is controlled by the pressuredrop occurring on expansion and by the rate of flow of the feedhydrocarbons. By such proper control a proper disintegration of the oiland a proper mixture is made in the reactor expander to obtain theresults of my process.

I have found, as a result of extensive experimentation, that thereaction between oil and oxygen-containing gas such as air, may becontrolled to produce high yields of high knock rating gasoline fromheavier oils, with low losses to gas and coke and with substantially noformation of products of combustion such as carbon monoxide and carbondioxide. Fuel oils, gas oil and kerosenes, may be converted to gasolinehydrocarbons, and gasoline hydrocarbons of low knock rating, such asparaflinio and naphthenic gasolines, into high knock rating gasolinefractions which contain high contents of aromatic hydrocarbons boilingin the gasoline range, by employing air to dehydrogenate and convert theoil without burning any substantial amounts of the feed hydrocarbons, asis evidenced in the process of this invention, by the formation of gasessubstantially free of carbon monoxide and carbon dioxide.

The reaction between air and oil at high temperatures occurs in a seriesof steps, involving the formation of alcohol, and as further oxygenreaction occurs, aldehydes are formed. The aldehydes may break down tocarbon monoxide and hydrogen, or the aldehydes may be burned completelyto carbon dioxide and Water. If suicient oxygen is available forcombustion, carbon monoxide is converted to carbon dioxide. Part of thealdehydes may be oxidized to acids. These acids are unstable at hightemperature and break down to carbon dioxide without reaction withoxygen. This chain process of combustion is Well known in the art ofcombustion and has been given the name of hydroxylation process ofcombustion. While I do not wish to be limited by this theory of chemicalcombustion, I believe that it may be accepted as a Valid explanation ofthe process of combustion. Whatever theory of combustion is used, it iswell known and I have been able to establish this fact in my ovmexperience, that if oxygen and air are mixed under conditions to permitthe establishment of the combustion process, that is, of this chain or"combustion reactions, the gases contain large quantities of carbonmonoxide. A large proportion of the oxygen used appears as carbonmonoxide in the gases and a substantial proportion of the feedhydrocarbons are converted to carbon monoxide. If an amount of air isused insufficient to cornpletely convert the feed hydrocarbons intocarbon dioxide and carbon monoxide, the process of combustion raises thetemperature of the hydrocarbons to thermal cracking temperature, underwhich conditions the oil is cracked into lighter hydrocarbons under acondition of imperfect combustion, with the generation of large amountsof coke and lamp black and a high conversion of the hydrocarbons to gas.These processes are characterized by the presence of relatively largeamounts of carbon monoxide in the gases, tell tale of imperfectcombustion. The generation of large amounts of coke and large conversionof the feed to gas, the presence of large percentages of carbonmonoxide, are among some of the characteristic features of imperfectcombustion cracking processes.

I have found that by the proper control of the reaction I am able todirect the reaction between the oil and air into an entirely differentchannel or course of reaction. Apparently the reaction proceedsprimarily as a cission dehydrogenation proces. In this process a majorproportion of the oxygen is used to abstract hydrogen from the moleculeto form water. This is accompanied by a cission reaction in whichhydrocarbons of lower molecular weight are formed. The gases aresubstantially free of carbon monoxide and in my process I have been ableto conduct the reaction so that no or only a trace of carbon monoxideappears in the gases. There is no free oxygen present and the gasformation and the amount of coke generated when operating on heavy oilsis far less and of a different order of magnitude than that present inimperfect combustion cracking reactions. rThe process of dehydrogenationand cission is accompanied or followed by procn esses of cyclization andaromatization, since I produce gasoline fractions of high aromaticcontent from hydrocarbons of naphthenic and parafnic nature. The processof conversion is accompanied by the formation of only small amounts ofcarbon dioxide. This I believe is a result of the conversion of theoxygenated bodies which form as a result of secondary reaction in thisprocess, These oxygenated bodies are in the inevitable consequence ofthe presence of the reaction between oxygen and oil. The amount ofcarbon dioxide and the percent of oxygen which goes to carbon dioxide istherefore an index of the oxygenation process which goes on and I havefound that by the proper control of the air while maintaining eiiicientconditions of mixing and expanding, I can keep this oxygenation processat a minimum, as evidenced by the very limited conversion of the oxygenand the feed to carbon dioxide.

I have observed. however, that under conditions of mv operation in whichthe control is such as to inhibit the formation of carbon monoxide, adehydrogen'ation cyclization process occurs in which the oxygen acts toextract hydrogen from the molecule to form aromatic type Qasolines.

While I do not wish to be limited to any particular theory of thephysical and chemical processes which occur and wish to embrace withinthe limits of my invention the full scope thereof within the claimsforming a part hereof, I believe that the reactions described belowexplains the results of and the process occurring in my invention. rIhisdehydrogenation reaction in my process apparently occurs preferentiallyto an extent suiicient to inhibit or prevent the combustion reaction.The hydroxylation process of combustion requires a relatively longseries of steps before the combustion chain is completed. If the oxygenis robbed from this process by another mechanism, as for instance, bythe dehydrogenation reaction of my process, then the chance for thecompletion of the chain of combustion will be materially reduced and theformation of carbon monoxide will be inhibited or prevented.

Ihave found that one of the important considerations in attaining myresults is the control of the mixing process and the control of theexpansion process in the reaction.

I have found that in a maldistributed condition of oil and gas in thereactor, at the temperature occurring in this process, there will be aregion in which the ignition and combustion takes place. By forming themixture in a uniform condition and by maintaining the composition of themixture, that is, the ratio of air to oil, and its pressure sufficientlylow, I am able to control the reaction in the reaction zone so thatignition and combustion do not occur and the reaction proceeds in thenon-combustion reaction region rather than in the combustion region orpartial combustion region.

The pressure in the mixer is always higher than in the reactor. Thepartial pressure of the oxygen is high both because the pressure is highand the condition at the initial stages of the mixing contains the oilin a maldistributed condition. There are regions in the mixer wherethere are high air/oil ratios.

The condition of ignition and combustion in the mixer is accelerated byincreasing temperatures in the mixer. t any given pressure in the mixer,and at any given ratio of oil to air, and for a given velocity of ow,there is a maximum temperature above which ignition and combustionstarts. I prefer to maintain the temperature in the mixer below thistemperature and to permit suiicient time in the mixing tube to form anintimate mixture. The mixture is discharged from the mixing tube beforeany substantial reactions between the oil and air occurs, as ishereinafter explained. When the reaction proceeds in the reactor it isaccompanied by a decreasing concentration of oxygen which is beingconsumed in the reaction to form water and some oxygenated bodies. Thereis also a rise in temperature. While this rise in temperature at thegiven pressure may tend to move the reaction in the direction of theignition and combustion range, this movement would be countered by thediminution in the oxygen partial pressure. A diminishing partialpressure takes a higher temperature to move the air-oil mixture to theignition range. The reaction occurring in my process is self-limiting,that is, has an automatic break. As will be observed from the dataherewith reported, the temperatures reached are far below those whichare attained in` combustion processes, and the conversion of air and oilto carbon monoxide and carbon dioxide are inhibited. Notwithstandingthat the temperature of the reactions are increased the reaction isstill maintained below the region of ignition with no formation ofcarbon monoxide.

But whatever theory is adopted to explain the results of my process, Ind that by a proper control of the process I am able to cause a highconversion of oil to high knock rating hydrocarbons with a low loss asgas and coke and substantially no loss of feed or formation of carbonmonoxide by imperfect combustion of the feed hydrocarbons.

This is attained in my process by forming the mixture at relatively lowtemperatures in a mixer, causing the mixture to expand into a lowerpressure Zone before the reaction between the air and the oil hasobtained either a combustion reaction or a substantial conversionreaction. It is preferable to discharge the air-oil mixture out of themixing tube before the reaction proceeds very far, in other Words,before the combustion chain is established. If this mixture is permittedto remain inthe mixing tube toolong the reaction between the air and oilin the maldistributed condition occurs in the mixing tube withrelatively high pressure air, or if a high mixing temperature ispermitted to exist in the mixing tube, the combustion chain would beestablished and a coking of the tube result.

The mixture when properly made is then expanded into the lower pressurechamber. Upon expansion the disintegration previously discussed occurs.The expansion, in addition to causing the disruption and disintegrationof the oil, also reduces the partial pressure of the oxygen. Thispartial pressure is further diminished by the presence of thehydrocarbon gases resulting from the reaction and consumption of theoxygen in the formation of water.

By imparting to the stream a sufficient energy of flow the expansion ofthe oil and air into a lower pressure expander disrupts the oil into ane fog of minute droplets of oil, uniformly dispersed in the atmosphereof air at a lower pressure. In other words before the combustion chainhas reached the stage where the oxygen is reacting to form oxygenatedbodies suiiicient to cause the formation of carbon monoxide and coke, i.e. before imperfect combustion is obtained, or before a temperature isattained to cause any material gasoline formation, the expansion of theoil into a low pressure zone causes a diminution in the concentration ofthe oxygen. The presence of an excess amount of hydrocarbons far inexcess of the amount of any alcohols and aldehydes which may possibly beformed by the initial oxygenation in the reactor apparently robs theoxygen from the hydroxylation-combustion reaction and the processproceeds mainly as a dehydrogenation reaction. the air and ranging up to100% of the air goes to this dehydrogenation reaction.

Air and oil is thus mixed to form a uniform mixture in which the oil7 ifit is liquid feed such as a residual oil, is mixed with air at atemperature below its incipent vaporation point, i. e. up to 5 to 10% ofthe oil vaporized, in order to prevent surges of vapor and liquid in themixture. If material partial Vaporization of a liquid feed is caused inthe mixer there will be sudden surges in the mixer causing impropermixtures of air and oil. This may result in momentary periods of highair/oil ratios of such magnitude as to cause the establishment ofimperfect combustion in the mixer with accompanying coking up of .f

the mixer. The mixture occurs preferably at a relatively lo-wtemperature below that which would give sufficient time in the mixingtube to cause the combustion chain to be established. The temperaturewill be sufficiently low to prevent any substantial conversion of theoil to gasoline in the mixing tube. Preferentially this mixing tube is aline mixer. The mixture is discharged into the expansion vessel ofvastly ircreased diameter before the reaction has progressed far enoughto attain an active reaction temperature.

The reaction of oxygen with oil proceeds through an induction period. Asair is mixed with oil at sufficiently high temperature there is a periodof time during which very little reaction occurs between the oxygen andthe oil and then the reaction begins to accelerate, rising rapidly witha resulting increase in temperature. The higher the mixing temperaturethe shorter this More than 59% of induction period. The mixture in themixing tube, if maintained in the mixing tube for a suiiicientv lengthof time, Will, at the high pressures and temperature in the mixing tube,complete the combustion chain and combustion will occur. The inhibitionof reaction in the mixing tube can be accomplished by controlling theconditions of temperature of mixing and the length of time the mixtureis in the mixing tube.

The mixture is expanded into an enlarged chamber in which a substantialpressure drop occurs. The reduced partial pressure of oxygen will, aspreviously explained, further inhibit the generation of the completionof the combustion chain. The reduction in pressure on the air and theincrease in temperature causes a tremendous expansion of the gas and avery large reduction in the oxygen concentration. The large quantity ofoil both in liquid and vapor form, as compared to the relatively smallquantity of oxygenated bodies, would create a condition wherein thedehydrogenation reaction would be preferred to the completion of thecombustion chain. The reaction therefore proceeds in the direction ofdehydrogenation. If a condition is established in which thestratification of the oxygen occurs, so that there are local high ratiosof oxygen to oil, there will be available sufficient oxygen for thecompletion of the combustion chain. Apparently also this would result inlocal high temperatures, notwithstanding that the average over-alltemperature would be low. At high temperature the combusion chainaccelerates and may accelerate to a higher degree than thedehydrogenation stage. The results would be imperfect combustion.

In the operation of my process, sufficient energy is imparted to thestream in the mixer and sufficiently high velocities are imparted sothat upon the expansion of the air-oil stream in the expander the dropin pressure across the orice and expansion and enlargement in volumethus obtained causes an extensive disruption and disintegration of theoil stream into minute fog-like droplets of `oil uniformly distributedin the atmosphere ofair. In such a condition with proper control oftemperatures and air rates, the oil and air undergoes a dehydrogenationreaction without formation of carbon monoxide. If, however, thisdisruptive energy is not available by reason of the fact that the airpressure or the oil rates are diminished, so that the pressure drop andvelocity of flow across the orifice formed by the juncture of the mixingtube and the expander does not give the desired expansion and thereforedoes no-t have the disruptive energy available, no proper disintegrationof the oil occurs, no proper mixture is formed. A phenomenon ofstratification of oil and air occurs, permitting oil to react with airunder various conditions, some of which may be such as to permitcombustion and the generation of excessive and local temperaturesresulting in excessive loss by degradation to gas, carbon monoxide andcarbon.

The velocities of ow of air or oil through the mixer may be too great,or the mixing tube too short, so as not to give suilcient time in themixer for an intimate commingling of the air and oil, and on discharge astratified condition will result. Itis desirable to provide sufficientmixing time in the mixer so that in cooperation with the energies offlow available the proper type of disintegration and distribution isobtained in the reac-tor-expander.

Additionally the rate of feed of the oil may be reduced to so low afigure that for the particular design of mixer, even though desirableair-oil rates are employed to give the reactions when mixing conditionsare properly established, the rate will be insulicient to give thedesired mixing and expansion. It will be found that within the limitsherein described, and taking due observance of the nature of theproducts produced, as herein described, a proper design of mixer andproper control can be attained.

For each mixer design there is a velocity or pressure drop, which ifreached or exceeded will give the necessary disruption and mixing. Thiswould vary with various mixer designs and a test which may be employedis the amount of carbon monoxide that is present in the gases. It Willbe found that if this desirable mixing and expansion is attained, thecarbon monoxide content of the gases will be substantially nil. If,however, this is not attained, then the carbon monoxide content of thegases will be high.

The mixture travels from the point of mixing through a short length oftubing of restricted cross-sectional area at high velocity and highturbulence and at relatively high pressure, to cause intimatecommingling of the air. The stream is discharged into a reactor ofgreatly enlarged cross-sectional area through which reactor it passes incommingled state without separation of components until it is dischargedat a remote end of the reactor. The temperature rises upon expansioninto the top of the reactor. The temperature at the top of the reactoris however below the maximum temperature obtained in the reactor. Iprefer to maintain the temperature in the mixing tube to below about 750F. so that I ensure substantially no reaction in the mixing tube. TheIreaction takes place substantially entirely in the reactor. This ensuresthat the reaction will not occur in the mixing tube where coke, if itaccumulates, will cause the process to be shut down.

The mixture enters the reaction vessel at a temperature near to or belowthe threshold rethe reactor varied from 250 F. to 730 F. The actiontemperature of lYU-'750 F. In the examples given below the temperatureat the top of the reactor varied from 250 F. to 730 F. The mixture ofair and oil travels through the reaction Vessel in commingled statewithout separation of the oil and gas in a thoroughly distributed anduniform mixture. The reaction proceeds in the passage of the streamthrough the reactor, with rise in temperature until the maximumtemperature is attained and a substantially complete utilization of theoxygen of the air occurs.

I maintain the mixture in the reactor sumciently long to permit theattainment of maximum temperature and preferably long enough to ensurethe substantially complete consumption of the oxygen of the air by thereaction.

I have found in the apparatus and process exemplied herein that if themixing temperature measured at the point where the mixing temperature ismeasured as described herein, attains 650 F. or higher, using airpressures at the inlet of the mixer of 95 lbs. or higher, cokingproceeds inside the mxing tube and the process is rapidly shut down.While this temperature may vary with different sizes of mixing tubes andpressures employed, and with stocks processed, it will be found that asthe temperature -proceeds above this point, and up to about rTO0-750"F., the tendency to coke in the tube increases, and

I prefer, as will be herein described, to control the mixing temperaturebelow about 750 F., and preferably not above around 650 F. to '750 F.,the lower temperature being preferred.

The maximum temperature rise obtained in the reactor-expander dependsupon the air/oil ratio employed. The more air employed per barrel offeed, the higher will be the rise in temperature from the mixingtemperature to the maximum reaction temperature attained in theexpander. l' have found thatthere is amaximum air ratio which may beprofitably employed to obtain this necessary temperature rise anddesired dehydrogenation reaction. The rate of conversion of th'e oil,that is, the percent of the oil which may be converted into gasoline,gas oil,

and other bodies under proper conditions of reaction as hereindescribed, to produce the dehydrogenation without any material formationof carbon monoxide, is a function of the temperature attained in thereactor. IThe higher the temperature the greater the yield of gasolineand other light products. I have found that I can, by the proper controlof reaction, obtain relatively high conversion temperatures Withoutcausing any combustion of the oil, or any material conversion of theoxygen to carbon monoxide.

The nature of the process is also further brought out by the characterof the products produced. The process may be operated to convert heavierfractions such as crude oil, fuel oil, gas oil, kerosene, into gasolineand gas oil fractions and in some cases into residuum and in others intocoke. The gasolines and light gas oils are of high aromatic content, asevidenced by the boiling points, gravities and viscosities. Thegasolines are of high octane rate, ranging from 75 to as high as 88octane and higher. It has been found that unlike other conversionprocesses, such as catalytic and thermal conversion processes, theproducts of the reaction such as the residuum and gas oils formed may berecycled into the process and upon reaction give yields of productssimilar to that of virgin unreacted feeds. So also may cracked products,such and gas oil and residuums produced by thermal or catalyticprocesses, be processed by my process.

In operating the process to produce coke, I have found that unlike thecoke formed in thermal cracking processes, which is massive coke andmust be cut out or bored out of the reaction vessels, the coke formed isin discrete particles like grains of sand apparently formed by thecoking of small droplets of oil.

I have found that in operating with sufficient air rate to supply thenecessary air for the dehydrogenation reaction, there is an initialtemperature, hereinafter referred to as threshold temperature which mustbe attained by the reaction between the oil and the air in order toobtain substantial conversion of the oil. This threshold temperaturewill change with various stocks which may be treated but it will befound that with each stock there will be such a temperature below whichno substantial conversion of the oil occurs. As this temperatureincreases it will be found that the yields increase. In operating with a17 A. P. I. gravity Los Angeles Basin fuel oil or with other types ofcrude or residuums or as produced in this process or by thermalcracking, it has been found that this temperature lies in the range ofabout 725 to about '750 F. Oil and air commingled at a temperature ofabove about 200 to 300 F. or higher, will attain this thresholdtemperature under proper conditions of operationnot by the combustion ofthe oil, but primarily by the dehydrogenation reaction. It has also beenfound that to obtain substantial conversion of the oil, it is desirableto employ air rates in excess oi about 900 to 1000 cubic feet of air perbarrel of oil. In this speciiication, wherever volumes of air or gas aregiven, it is to be understood that the volume is measured at 60 F. and14.7 pounds absolute pressure. Wherever liquid volumes are given it isunderstood they are measured at 60 F. This ratio will vary with thestock charged, but it will be found that for heavy oils such as the LosAngeles Basin mixed base fuel oils, or other residuum oils as describedabove, this threshold value of the air rate is desirable to obtain asubstantial conversion of the oil. The

temperature rise which occurs as a result of the reaction of the oilincreases as the air rate is increased.

As the maximum temperature attained in the reactor, which temperaturehereafter will be termed the maximum reactor temperature rises, theyield of 400 end point gasoline rises. However there is also a rise inthe amount of the charge which is converted into fixed gases lighterthan gasoline and when operating on a fuel oil charge an increase in thetotal losses, i. e. gas, coke and other losses. There will be aneconomic limit as to the temperature which is to be employed and I havefound that for economic operations the temperature limits may be takenapproximately from 800 to 1100 F.

I prefer to cause the temperature rise from about '700 to 750 F. to themaximum reactor temperature, i. e. to 800 to 1l00 F. to occur in thereaction vessel during the travel of the mixed oil and air therethrough.The chamber is designed to give sufficient time to permit of thisreaction between the air and oil while traveling through the chamber.

With these criteria in it will be found that the useful range oftemperature and air rates may he taken as about 200 F. to 700 F. in themixer, 800 F. to 1100 F. as the maximum reactor temperature and fromabout 900 to 4000 cubic feet per barrel of oil as the air rates to beemployed. It will be found that by properly choosing the temperaturesand air rates in the ranges and by properly controlling the air rate,high yields ci gasoline of high octane and low loss of feed to coke andgas may be obtained with but a minimum utilization of air and aconsequent minimum amount of combustion of the feed and a minimumformation of oxidized products.

This process will be better understood by reference to the accompanyingdrawing which shows a schematic illustration of one application of myprocess.

Oil from a source of supply is fed through line I under pressure by a'pump 2 to the coils 4 positioned in furnace 3 which furnace is heated byburners 5. The preheated oil enters the run 6 of the T mixer l. Into thebranch 8 of the T mixer I air is introduced under pressure through lineI controlled by valve 9. The oil and air mixes in the mixer 1 and inline II and is expanded into an enlarged combined reaction, coking andseparating vessel I2. The oil and air passes in commingled state withoutseparation of component parts through I 2 until it gets to the outletline I3.

At this point there is a separation oi components.

The coke particles, as will be later explained, continue downwardly anddeposit in the lower part of the reactor I2 to be dischargedcontinuously through the outlet The vapors and any unseparated cokeparticles exit through line I3 into the separator i4. In the separatorthe vapors continue upwardly while the coke drops out and down into thelower part of the separator I4, to be withdrawn through line 'il' asexplained later. The vapors exit through line I5 and enter through lineI6 into the rectifier Il. In this rectier the vapors are separated intoa heavy gas oil fraction which forms a bottoms and into lighterfractions. The heavy gas oil is withdrawn through line I8 by control ofvalve I9 and pump 20. This gas oil may be recirculated to be mixed withthe feed for reprocessing. The lighter fractions exit as vapors throughline 2i into the rectier 22. In this rectifier the vapors are separatedinto gasoline and lighter components and an intermediate or light gasoil fraction. This light gas oil fraction is withdrawn through line 23by pump 24 and by the proper control of the valves 25 and 2l part of thewithdrawn gas oil fraction is introduced as a reflux medium through line26 into the rectifier il and the other part is passed through line 23 aswill be furthed described. The gasoline and lighter fractions arewithdrawn through line 29 as vapors, condensed in condenser 30 andcollected in receiver 3i. The crude gasoline condensate is withdrawnthrough line 32 by pump 33 and by the proper control of the valves 34and 35 part is returned through line 31 to act as a reiiux medium inrectifier 32 and the other part is withdrawn through line 3S. Theuncondensed fractions consisting of the fixed gas and the uncondensedgasoline fractions, is withdrawn through line 3S and introduced into theabsorber 39 wherein it is washed with a menstruum which is introducedthrough line 46 as will be later described. In this absorber thegasoline fractions are removed and the fixed gases, substantially freedof gasoline fractions, are withdrawn through line 40. Part of thestripped dry gases are discharged under control of valve 50 through theline 5I. Another part is passed through line 52 and recompressed bycompressor 53 and introduced into headers 5l and 54 to be used in theprocess by proper control of valves 55 and 56. A portion of the lightgas oil passing through line 28 is discharged through line 4I controlledby valve 42 to a convenient receiver. Another portion passes throughline 43 into the heat exchanger 44 and through cooler 45 to beintroduced through line 45 into absorber 39 from which absorber the fatoil passes through line 41 from 48 and interchanger 44 and through line49 to the rectifier 22 in which it is stripped of its gasolinefractions.

Referring now to the handling of the coke, the coke which, as will belater described, is granular in the form of discrete particles,discharges through the discharge throat 5S of reactor I2 or dischargethroat 'II of separator I4. The Coke removing means is shownschematically at 59 and 12. This is one of the many methods by whichsuch granular solid material may be moved and it is not intended as alimitation upon such method of movement but merely an illustration ofone convenient method which I prefer. This Dump 1s a combination of ascrew and a pneumatic conveyer. The solids passed by the screws 59 andI2 rotated respectively'by motors 6u and 73, and 1s fed through an airchamber where it ls met by'numerous jets of gas introduced through thegasY rings lil and ill from headers E'i'and ll respectively via linesEll and 'l0 under the control of valves 65 and l?. This gas aerates thematerial and expands and causes it to flowf There is provided dust seals652 and l5. The material flows through line S3 and i3 respectively, inwhich lines it meets additional gas introduced through line titicontrolled by valve 6l and line 19 controlled by Valve 'i9'. The form ofpumphere illustrated is a well known type of pump forsolid particles,and no novelty is claimed for this particular pump constructionv formoving the solids, except when used in the combinations and sub--combinations shown in this application.

The mixture of vapors andV solids and gases traveling through lines b3and 'i3 may be introduced into one of `a number of receivers which aremanifolded so that they can be used inde- 'pendently of each other. Tworeceivers 82 and 'I0 y" rial discharges through these lines into theseparator 82. Valve 90 being closed, valve $32 being opened, the vaporsand gases separate from the coke which is deposited in the receiver 82to aocumulate therein. With valve 98 closed and valve Si and valve@f-opened, valve 93 being closed, the i:

mixed vapor and gases enter through line 95 into the rectifier il.Receiver 'le now having cooled as explained herein, it is opened througha man hole provided therein, and not shown, and the coke discharged inany convenient manner to the atmosphere. The receiver is then closed; Itis deaerated by opening valve S8, gas passing through the receiver, line9d', valve l0! being opened, valve $23 closed, the gas dischargedthrough une les and une se. Thus, gas win disif.'

place the air. When the receiver has been deaerated it is now ready toreceive the discharge from the separators and reactors. Receiver 82 nowbeing full, the valves 36 and 8d are closed and valves 63 and 8l areopened, valve liclosed,

valves 93 and S5 opened, 88 closed, valve 97 closed, valve 98 opened andvalve 92 opened. The coke is allowed to cool in the receiver 82, gasventing through valve 98 and line 9d. Cooling may be accelerated bypassing a coolant through F.'

the mass as for instance by passing gases through line 89, valve 99being opened, valve 92 being opened, valve 98 being opened, valve Siremaining closed, valve l ill remaining closed. When the coke has cooleddown suiiciently, valve S0 being closed, valve 92 being closed, theseparator 82 is f opened and the coke discharged, and the cycle is thenrepeated for these carbon receivers as is explained.

In carrying out the process of this invention and this apparatus, thecontrol is directed to the formation of coke and vaporous fractions andnot to the formation of a liquid residue. The purpose of the process isto form a solid dry coke which is in such discrete particles of suchrelatively small size that it may be discharged continuously from thereactors and separated. There is thus produced a continuous cokingprocess. The oil is preheated in heater 3. It is desirable to preheatthe oil to a temperaturenot higher than the incipient vaporizationtemperature, that is, to vaporize not much more than .Fa-10% of the feedstock. A partially vaporized stock or a stock heated to high temperaturewill be materially vaporized on mixing-with air and surges will occur inthe mixer. Such surges cause uneven mixing, maldistributed oil and airmixture, excessive local air/oil ratios, carbonization and excessivegasication. This may result in a clogged mixer due to accumulation ofcoke.

The preheated oil is commingled with air under conditions of controlpreviously recited, such as to cause a conversion of the oil directlyinto coke and vapors without any substantial formae. tion of liquidresidue or of carbon monoxide,

that is, without any substantial combustion of the oil. The oil ispreheated to such a temperature that at the air rates and temperaturesair employed, the temperature of the mixture cf Yoil and air shall benot over about 650 to 750 F., preferably not over about 650 F.' Therates of flow of the products are correlated to the sise of the reactorand to the size of the mixer, to obtain the control wherebysubstantially no formation of carbon monoxide is formed as is explainedabove. Thus the air and the oil may be introduced into the mixer at apressure of about to 140 pounds and the pressure in the reactor ismaintained at about 35 pounds.

As an example of a useful ratio of the diameter f of the mixer nozzle tothe diameter of the reactor, wherein the results of this process areobtained at the ratio of about to 1, as given as an illustration. Whileone line mixer I is shown, it is understood of course that a pluralityof such mixers may be employed in parallel, all discharging into thereactor l2. By the proper regulation of the feed rates of oil and thefeed rate of air correlated to the mixer and reactor design and thepressures employed, the reaction may be controlled so as to produce atemperature at the top of the reactor of about 700 F. upward. Thetemperature rises as the mixture passes through the reactor until partway down it reaches a temperature of about 900 to 950 F. It has beenfound that if the maximum temperature attained is controlled to be inexcess of about 900 F. and preferably above 925 F., under the conditionshere described, the oil is completely converted to coke and to vaporousproducts, no liquid residue being formed.

In operating my process I commingle the oil and air at the chosentemperature and rates as expanded herein. The mixture is commingledunder suciently high pressure and ow rates to pass the products at highvelocity through the mixing tube. The time permitted in the mixing ispreferably insufficient to raise the temperature to or materially abovethe threshold reaction temperature as hereinafter explained, withsucient time in the mixer to cause proper mixing, but preferably asufficiently small period of time in the mixing nozzle to preventmaterial reaction, as explained above. observance Yof the principlesdescribed herein will permit a proper design of the mixer and expandercombinations and a proper choice of operating-conditions.

The mixture is discharged preferably substantially unreacted as abovedescribed, from the mixing tube intothe reaction vessel, Ywhich is manytimes greater in volume and diameter than the mixing tube. There is aconsequent large drop in pressure. This drop in pressure and expansionensures a disintegration of the oil into minute droplets nely dispersedthrough the gaseous atmosphere. There is therefore a unlformdistribution of oil in the air. Reaction occurs and temperature risesrapidly from the threshold temperature which occurs near the top of thereactor to the maximum reaction temperature attained in travel throughthe reactor. The oil is converted while in a disintegrated condition inthe form of fine droplets. The mixture travels through the reactor andis discharged at the bottom, the oxygen in the air being completelyconsumed.

If the temperature attained is about S90-950 F. or higher the fuel oilfeed is completely converted into vaporous products and coke. The cokeis granular in nature due to the coking of the fine droplets of oil. Itis collected in the bottom of the separator and reactor and is removedas described.

As an example for carrying out the process, a. feed composed of LosAngeles Basin residuum having a gravity of 17 A. P. I., flash of 230,viscosity of 103 seconds Saybolt Universal at 122 F., and having aninitial of about 470 F. and distilling olf at 570 F., is preheated to atemperature of about 540 F, and mixed with air charged at about 80 F. atthe rate of about 2350 cubic feet per barrel of oil, the temperatureattained in the mixer was about 300 F., the temperature attained at thetop of the reactor is 700 F. and the maximum temperature attained in thereactor l2 is 928 F., and the temperature at the point of discharge fromthe reactor |3 is about 820 F. The size of the mixer 1 in this examplewas M3 internal diameter and the internal diameter of the reactor was2.0 inches. The air and oil pressure was about 130 pounds gauge at themixer and the pressure in the reactor was 35 pounds gauge. There wasproduced 28.5% of gasoline as later described, 18.5% of a light gas oil,15.5% of a heavy gas oil and no residuum. The coke deposited was of agranular nature having the appearance of sand. The coke was light andnot massive. The gasoline was of the following nature:

A. P. I. gravity degrees 49.3 A. S. T. M.-C. F. R. knock rating 75.8Reid vapor pressure pounds 10.2 Engler distillation:

Initial degrees F. 98 do 132 50% do 238 90% do 356 End point d0 397 Theheavy gas oil such as is removable through line I8 had the followingcharacteristics:

A. P. I. gravity degrees 5.7 Viscosity, S. F. at 122 F seconds 1235 Thematerial such as will be removed through line 23 is a light gas oilhaving the following characteristics:

A. P. I. gravity degrees 23 Viscosity, S. U. at 100 F seconds 38Distillation:

Initial degrees F. 403

End point do 653 In this process the oil is heated in furnace 3 tovarious temperatures at or below the incipient vaporization temperatureof the oil. It is desired that no substantial vaporization of the oiloccurs in order to insure proper mixing conditions. The mixertemperature, as described above, should be below the threshold reactiontemperature, which for the oils of the nature illustrated in theexample, run from 70D-750 F. It has been found, however, that it isdesirable to maintain the temperature below 650 F., since if vthe mixertemperature is allowed to rise to 650 F. or higher excessive cokingoccurs and the mixer tends to stop up when employing a feed asillustrated above. By carrying the temperature in the range of 900 F.and higher and preferably above 925 F. to 950 F., the oil, if it is ofthe residual nature such as described above, is converted directly tocoke.

The temperature rise which occurs between the mixer temperature and themaximum reactor temperature, as illustrated above, is a function of theair/oil ratio, and the same reactor temperatures are attained byincreasing the temperature of the feed and decreasing the ratio of airto oil. Thus, instead of using 2350 cubic feet per barrel of oil and amixer temperature of 300 F., the same reactor temperature could beobtained by controlling the temperature of preheat and air/oil ratio togive a mixer temperature of 550 F. and an air/oil ratio of about 1750cubic feet per barrel of oil. Or, the air/oil ratio may be increased to3000 cubic feet per barrel and the mixer temperature reduced to about228 F. by dropping the temperature of preheat and the above reactortemperature obtained. It has been found, however, that it is notdesirable to raise the mixer temperature to above about 650 F. nor todrop the air/oil ratio below about 900-1000 cubic feet per barrel ofoil. For practical purposes it will be found that in the range of amixer temperature below about 600 F. and an air/oil ratio above about1350 cubic feet per barrel of oil to a mixer temperature of about 200 F.and an air/oil ratio of about SOOO-3500 cubic feet per barrelillustrates useful ranges of reactor temperatures and air/oil ratioswhereby temperatures of around 900 F. to 950 F, may be attained in thisprocess to cause the conversion of residual fractions directly to cokeand gas oil and gasoline.

When controlled as herein described, it will be found that the processproceeds with substantially no combustion of the oil. The nxed gaseswill contain substantially no carbon monoxide and these may be as low asfrom 0 to .05% and will contain carbon dioxide from 0 to 2.5%,percentages being volume percent of the wet gases issuing from receiver3i. Less than .1% to not much more than .6% of the feed will beconverted into carbon dioxide, and from less than 5% to not much morethan 12-15% of the air will be converted into carbon dioxide. From70-90% of the oxygen appears as water in the process, depending on theair/oil ratios used. The loWer the air/oil ratios used the smaller theamount of oxygen which will be converted to carbon dioxide and whichwill be used in converting the fuel to carbon dioxide and the higher thepercentage of the oxygen which will appear as water.

The foregoing description of the process of the invention and theexperimental data are not to be construed as limiting my invention, asthey have been given for illustrative purposes only and changes andmodifications may be made therein within the scope of the appendedclaims.

I claim:

1. A continuous process for converting residual oil into gasoline andgas oil fractions and into coke which comprises preheating oil to notmore than the incipient vaporization temperature of said residual oilwhile still substantially in the liquid state, commingling said oil withair in a tube of restricted cross sectional area at a temperature belowabout G50-750 F., discharging said commingled air and oil from said tubebefore said temperature reaches above ab ut 750-800 F., while still in aliquid state commingled with the air introduced into said mixing tubeand before a gasoline or carbon monoxide forming reaction occurs, intoand through an enlarged space, at a materially reduced pressure, incommingled form without any substantial separation of liquid oil fromsaid air, for a time to permit the temperature to rise to activeconversion temperature of at least about 900-950o F. without combustionof said oil, substantially completely converting said liquid oil intonely divided particles of coke and into vaporous and gaseous fractionslighter than said oil charged to the process, said lighter fractioncomprising gasoline, hydrocarbon fractions lighterthan gasoline andgaseous fractions substantially free oi carbon monoxide or carbondioxide, said conversion and said temperature rise occurring solely byreaction between the air introduced into the said mixing zone and undera diminishing partial pressure of oxygen in said expansion zone,separating gasoline and coke from said products of reaction.

2. A continuous process for converting residual oil into gasoline andgas oil fractions and into coke which comprises preheating oil to notmore than the incipient vapo-rization temperature oi said residual oilwhile still substantially in the liquid state, commingling said oil withair in an unheated tube of restricted cross sectional area at atemperature below about`650-750" F., discharging said commingled air andoil from said tube before said temperature reaches above about 750-800F., while still in a liquid state commingled with the air introducedinto said mixing tube-and before a gasoline or carbon monoxide formingreaction occurs, into and through an enlarged space, at a materiallyreduced pressure, in commingied form without any substantial s eparationof liquid oil from said air, for a time to permit the temperature torise to active conversion temperature of at least about 900-950 F.without combustion of said oil, substantially completely converting saidliquid oil into finely divided particles of coke and into vaporous andgaseous fractions lighter than said oil charged'to the process, saidlighter fraction comprising gasoline, hydrocarbon fractions lighter thangasoline and gaseous fractions substantially free of carbon monoxide orcarbon dioxide, said conversion andy said temperature rise occurringsolely by reaction. between the air introduced into the said mixing zoneand under a diminishing partial pressure oi oxygen in said expansionZone, and separating gasoline and coke from said products of reaction.

3. A continuous process of converting residual oil into gasoline andinto gas oil fractions and into coke, which comprises preheating oil tothe incipient vaporization temperature of said residual oil while stillsubstantially in the liquid state, commingling said oil with air in atube of re-` stricted cross sectional area at a rate in excess oi 1000cubic feet per barrel of oil, controlling this ratio of air to oil andthe temperature of preheat of said oil and said mixing to obtain atemperature of the mixture not above about 650 F. and adjusting said airand oil flow and said temperatures to discharge said air and oil fromsaid mixing tube in substantially unvaporized form and before a gasolineor carbon monoxidev asesor? forming reaction between said liquid oil andair occurs in said tube, expanding said mixture oi oil and air from saidtube into a chamber oi much greater cross sectional-area maintained at apressure materially lower than the pressure in said tube, wherein saidoil is disrupted into iine particles of oil, controlling said rate ofiiow in said tube by controlling the rate of feed of said oil and saidair to discharge said mixture into said enlarged reaction space wherethe temperature of the oil reaches an active conversion temperatuesolelir by reaction of the oil and air introduced into said mixing tube,passing said stream of air and oil particles in said reaction space in acommingled state without separation of the parts of said stream untilsaid stream has reached a temperature in excess of around 900 F. to 950F. under continuously diminishing partial pressure of oxygen withoutcombustion of saidl oil to carbon monoxidacontinuing said passage untilsaid particles ofoil have been completely converted into granularparticles of coke and vaporous products, then separating the vapors fromsaid coke, and separating a high knock rating aromatic gasoline from'said vapors and separating a fixed gas from said gasoline substantiallyfree of carbon monoxide and oxygen.

4. A process of converting residual oil into gasoline and into gas oilfractions and into coke, which comprises preheating oil to the incipientvaporization temperature of said residual oil, commingling said oil withair in a tube of restricted cross sectional area at a rate of 1000 to4000 cubic feet per barrel of oil, controlling this ratio of air to oiland the temperature of preheat of said oil and said mixing to obtain atemperature of the mixture not above about 200 F. to 700 F. andadjusting said air and oil ilow and said temperatures to discharge saidair and oil fromY said mixing tube in substantially unvaporized form andbefore a gasoline or carbon monoxide iorming reaction between saidliquid oil and air occurs in said mixing tube, expanding said mixture ofoil and air from said tube into a chamber of much greatercross-sectional area maintained at a pressure materially lower than thepressure in said tube, passing said stream of air and oil in saidreaction space in a commingled state without separation of the parts ofsaid stream until said stream has reached a temperature upward or about900 F. to 950 F. without material conversion of said air to carbonmonoxide under continuously diminishing partial pressure of oxygenwithout combustion of said oil, continuing said passage until said oilhas been completely converted into granular coke and vaporous products,then separating the vapors from said granular coke and separatinggasoline from said vapors and separating a xed gas from said gasolinesubstantially free'of carbon monoxide.

5. A process of converting residual oil into gasoline and into gas oilfractions and into coke, which comprises preheating oil tothe incipientVaporization temperature of said residual oil,

commingling said oil with air in a tube of re stricted cross sectionalarea at a rate in excess of 1000 cubic feet per barrel of oil,controlling this ratio of air to oil and the temperature of preheat ofsaid oil andsaid mixing to obtain a temperature of the mixture not aboveabout 650 F. and adjusting said air and oil flow and said temperaturesto discharge said air and oil'irom said mixing tube in substantiallyunvaporized form and before a gasoline or carbon monoxide formingreaction between said liquid oil and air occurs in said mixing tube,expanding said mixture of oil and air from said tube into a chamber ofmuch greater cross-sectional area maintained at a pressure materiallylower than the pressure in said tube, passing said stream of air and oilin said reaction space in a commingled state without separation of theparts of said stream under continuously diminishing partial pressure ofoxygen without combustion of said oil until said stream has reached atemperature in excess of around 900 F. without material conversion ofsaid air to carbon monoxide, continuing said passage until said oil hasbeen completely converted into coke and vaporous products, thenseparating the vapors from said coke and separating gasoline from saidvapors and separating a xed gas from said gasoline substantially free ofcarbon monoxide.

6. A process of converting residual oil into gasoline and into gas oilfractions and into coke, which comprises preheating oil to the incipientvaporization temperature of said residual oil, commingling said oil withair in a tube of restricted cross sectional area at a rate in excess of1350 to 3500 cubic feet per barrel of oil, controlling this ratio of airto oil and the temperature of preheat of said oil and said mixing toobtain a temperature of the mixture of about 200 F. to 600 F., expandingsaid mixture of oil and air from said tube into a chamber of muchgreater cross-sectional area maintained at a pressure materially lowerthan the pressure in said tube, controlling said rate of flow in saidtube by controlling the rate of feed of said oil and said air todischarge said mixture into said enlarged reaction space before saidtemperature has reached an active conversion temperature of upward of750 F., passing said stream of air and oil in said reaction space in acommingled state without separation of the parts of said stream undercontinuously diminishing partial pressure of oxygen without combustionof said oil until said stream has reached a temperature in excess ofaround 900 F. to 950 F. without any substantial con- Version of said oiland air to carbon monoxide, continuing said passage until said oil hasbeen completely converted into granular coke and vaporous products, thenseparating the vapors from said granular coke and separating gasolinefrom said vapors and separating a lixed gas from said gasolinesubstantially free of carbon monoxide.

DAVID B. BELL.

CERTIFICATE OF CORRECTION. Patent No. 2,556,057. December 7, 19MB,

DAVID B. BELL.

It is hereby certified that error appears in the printed specificationof the above numbered patent requiring cor-reati on as follows: Page li,first column, line b5, strike out the words "the reactor varied from2500 F. to 'Z500 F. The; and second column, line M8, for "and gas" read--as geen; page 6, second column, line 5h, for "expanded" read--explained'; and that the said Letters Patent should be read with thiscorrection therein tha the same may conform to the record of the case inthe Patent Office.

signed and sealed this 15th day of February, A. D. 19th.

Henry Van Arsdale, (Seel) Acting Commissioner of Patents.

CERTIFICATE 0F CORRECTION. Patent No. 2,556,057. December 7, 19M.

DAVID B. BELL.

It is hereby certified that error appears in the printed specificationof the above numbered patent requiring Correcti on as follows: Page i4.,first column, line M5, strike out the words "the reactor varied from2500 F. to 7500 F. The"; and second column, line'LLS, for "and gas" read--as gas; page 6, second Column, line 51p, for "expanded" read-explained; and that the said Letters Patent should be read with thisCorrection therein the. the same may conformi to the record of the Casein the Patent Office.

Signed and sealed this 15th day of February, A. D. 19111;.

Henry Van Arsdale, (Seal) Acting Commissioner of Patents.

